#!/usr/bin/env bash
#
# Summary: Install a Python version using python-build
#
# Usage: pyenv install [-f] [-kvp] <version>
#        pyenv install [-f] [-kvp] <definition-file>
#        pyenv install -l|--list
#
#   -l/--list        List all available versions
#   -f/--force       Install even if the version appears to be installed already
#
#   python-build options:
#
#   -k/--keep        Keep source tree in $PYENV_BUILD_ROOT after installation
#                    (defaults to $PYENV_ROOT/sources)
#   -v/--verbose     Verbose mode: print compilation status to stdout
#   -p/--patch       Apply a patch from stdin before building
#   -g/--debug       Build a debug version
#
# For detailed information on installing Python versions with
# python-build, including a list of environment variables for adjusting
# compilation, see: https://github.com/yyuu/pyenv#readme
#
set -e
[ -n "$PYENV_DEBUG" ] && set -x

# Provide pyenv completions
if [ "$1" = "--complete" ]; then
  exec python-build --definitions
fi

if [ -z "$PYENV_ROOT" ]; then
  PYENV_ROOT="${HOME}/.pyenv"
fi

# Load shared library functions
eval "$(python-build --lib)"

usage() {
  # We can remove the sed fallback once pyenv 0.4.0 is widely available.
  pyenv-help install 2>/dev/null || sed -ne '/^#/!q;s/.//;s/.//;1,4d;p' < "$0"
  [ -z "$1" ] || exit "$1"
}

definitions() {
  local query="$1"
  python-build --definitions | grep -F "$query" || true
}

indent() {
  sed 's/^/  /'
}

unset FORCE
unset KEEP
unset VERBOSE
unset HAS_PATCH
unset DEBUG

parse_options "$@"
for option in "${OPTIONS[@]}"; do
  case "$option" in
  "h" | "help" )
    usage 0
    ;;
  "l" | "list" )
    echo "Available versions:"
    definitions | indent
    exit
    ;;
  "f" | "force" )
    FORCE=true
    ;;
  "k" | "keep" )
    [ -n "${PYENV_BUILD_ROOT}" ] || PYENV_BUILD_ROOT="${PYENV_ROOT}/sources"
    ;;
  "v" | "verbose" )
    VERBOSE="-v"
    ;;
  "p" | "patch" )
    HAS_PATCH="-p"
    ;;
  "g" | "debug" )
    DEBUG="-g"
    ;;
  "version" )
    exec python-build --version
    ;;
  * )
    usage 1
    ;;
  esac
done

unset VERSION_NAME

# The first argument contains the definition to install. If the
# argument is missing, try to install whatever local app-specific
# version is specified by pyenv. Show usage instructions if a local
# version is not specified.
DEFINITION="${ARGUMENTS[0]}"
[ -n "$DEFINITION" ] || DEFINITION="$(pyenv local 2>/dev/null || true)"
[ -n "$DEFINITION" ] || usage 1


# Define `before_install` and `after_install` functions that allow
# plugin hooks to register a string of code for execution before or
# after the installation process.
declare -a before_hooks after_hooks

before_install() {
  local hook="$1"
  before_hooks["${#before_hooks[@]}"]="$hook"
}

after_install() {
  local hook="$1"
  after_hooks["${#after_hooks[@]}"]="$hook"
}

# Load plugin hooks.
for script in $(pyenv-hooks install); do
  source "$script"
done


# Set VERSION_NAME from $DEFINITION, if it is not already set. Then
# compute the installation prefix.
[ -n "$VERSION_NAME" ] || VERSION_NAME="${DEFINITION##*/}"
[ -n "$DEBUG" ] && VERSION_NAME="${VERSION_NAME}-debug"
PREFIX="${PYENV_ROOT}/versions/${VERSION_NAME}"

[ -d "${PREFIX}" ] && PREFIX_EXISTS=1

# If the installation prefix exists, prompt for confirmation unless
# the --force option was specified.
if [ -z "$FORCE" ] && [ -d "${PREFIX}/bin" ]; then
  echo "pyenv: $PREFIX already exists" >&2
  read -p "continue with installation? (y/N) "

  case "$REPLY" in
  y* | Y* ) ;;
  * ) exit 1 ;;
  esac
fi

# If PYENV_BUILD_ROOT is set, always pass keep options to python-build.
if [ -n "${PYENV_BUILD_ROOT}" ]; then
  export PYTHON_BUILD_BUILD_PATH="${PYENV_BUILD_ROOT}/${VERSION_NAME}"
  KEEP="-k"
fi

# Set PYTHON_BUILD_CACHE_PATH to $PYENV_ROOT/cache, if the directory
# exists and the variable is not already set.
if [ -z "${PYTHON_BUILD_CACHE_PATH}" ] && [ -d "${PYENV_ROOT}/cache" ]; then
  export PYTHON_BUILD_CACHE_PATH="${PYENV_ROOT}/cache"
fi

# Default PYENV_VERSION to the friendly Python version. (The
# CPython installer requires an existing Python installation to run. An
# unsatisfied local python version can cause the installer to
# fail.)
if [[ "${VERSION_NAME}" == [23]"."* ]]; then
  export PYENV_VERSION="$(pyenv-whence "python${VERSION_NAME%%.${VERSION_NAME##*.}}" 2>/dev/null | tail -1 || true)"
fi


# Execute `before_install` hooks.
for hook in "${before_hooks[@]}"; do eval "$hook"; done

# Plan cleanup on unsuccessful installation.
cleanup() {
  [ -z "${PREFIX_EXISTS}" ] && rm -rf "$PREFIX"
}

trap cleanup SIGINT

# Invoke `python-build` and record the exit status in $STATUS.
STATUS=0
python-build $KEEP $VERBOSE $HAS_PATCH $DEBUG "$DEFINITION" "$PREFIX" || STATUS="$?"

# Display a more helpful message if the definition wasn't found.
if [ "$STATUS" == "2" ]; then
  { candidates="$(definitions "$DEFINITION")"
    if [ -n "$candidates" ]; then
      echo
      echo "The following versions contain \`$DEFINITION' in the name:"
      echo "$candidates" | indent
    fi
    echo
    echo "You can list all available versions with \`pyenv install --list'."
    echo
    echo "If the version you're looking for is not present, first try upgrading"
    echo "pyenv. If it's still missing, open a request on the pyenv"
    echo "issue tracker: https://github.com/yyuu/pyenv/issues"
  } >&2
fi

# Execute `after_install` hooks.
for hook in "${after_hooks[@]}"; do eval "$hook"; done

# Run `pyenv-rehash` after a successful installation.
if [ "$STATUS" == "0" ]; then
  pyenv rehash
else
  cleanup
fi

exit "$STATUS"